Definition of "dunna"

Ma lass!' he murmured. 'Ma little lass! Dunna let's fight! Dunna let's niver fight! I love thee an' th' touch on thee. Dunna argue wi' me! Dunna! Dunna! Dunna! Let's be together.'

1928, D[avid] H[erbert] Lawrence, chapter XIV, in Lady Chatterley’s Lover, authorized British edition, London: Martin Secker […], published February 1932 (May 1932 printing)